The atlas groups these together not to dismiss them but to be accurate about their history, which their own presentation often obscures. The Celtic tree calendar is Graves's poetic reconstruction, not a calendar the ancient Celts kept; the Armanen runes are List's eighteen-rune row built from a vision, not a historical futhark; the Dreamspell borrows the tzolkin's structure but uses a different correlation to the Western calendar than the traditional Maya count.
Distinguishing a modern revival from the ancient source it draws on is a service to both, and each entry states plainly what is old, what is new, and who made it.
Sources The White Goddess: A Historical Grammar of Poetic MythRobert Graves with The Occult Roots of Nazism: Secret Aryan Cults and Their Influence on Nazi IdeologyNicholas Goodrick-Clarke, Dreamspell: The Journey of Timeship Earth 2013Jose Arguelles